See What Founding Twitter Buys You

It's far from the majority of his wealth: Twitter was recently valued at a cool $1 billion, and Williams previously sold Blogger to Google before the search engine's lucrative 2004 IPO -- which one presumes is how he afforded the loft in the first place.

Turner also touts the loft's proximity to SoMa's "world-class dining and nightlife." Not that that's any use to a new dad.

The couple is building a new, modern house which Morishige Williams is designing. They hope to have it built in 2010 -- which raises the question of where the Williams family will live if the loft sells quickly.